1835.] Improvements in Science. 199 



this it is necessary to filter again and evaporate, and this 

 treatment should be repeated four times. A liquid is thus 

 obtained, which, on evaporation to dryness, leaves a residue 

 completely soluble in cold water. This new solution is 

 deprived of its colour by animal charcoal, purified and pre- 

 cipitated by alcohol. The precipitate is thrown on a filter 

 and washed with alcohol at the temperature 176° ; it is then 

 dissolved in the least possible quantity of hot water, and the 

 liquid submitted to a gentle heat. The substance thus 

 obtained consists of 



Oxygen . . 53*15 

 Carbon . . 39*72 

 Hydrogen. . 7*13 



100*00 

 It possesses a slightly yellowish colour when dry ; white 

 when hydrous, and is destitute of taste and smell. In thin 

 portions it is transparent, and is easily reduced to powder. 

 M. Biot found, on examining an aqueous solution of amidone, 

 that it produced upon the polarized rays of light a deviation 

 towards the right three times as great as cane sugar. When 

 heated in the air or in vaccuum, it fuses, swelling up, with- 

 out volatilizing. Cold water dissolves it completely, be- 

 coming very mucilaginous, but it is more soluble in hot 

 water. It is insoluble in alcohol and sulphuric ether. It 

 adheres so powerfully to the porcelain vessels in which it is 

 evaporated, that, in Varry's experiments, the glaze was 

 frequently removed although great precautions were em- 

 ployed. The aqueous solution becomes acid in some days. 

 Nitric and muriatic acids produce in the cold with amidine 

 solutions which are coloured strongly blue by iodine. It is 

 not so soluble in sulphuric acid. Its solution in potash, 

 when neutrallized by an acid, is coloured blue by iodine, 

 which detects the presence of amidine in a solution containing 

 but a minute quantity of it. Nitric acid converts it into 

 oxalic acid ; 100 parts of amidine and 250 parts of sulphuric 

 acid, at C 150°, affords 95*80 parts of anhydrous sugar. 

 The dextrine of Biot and Persoz appears to be an impure 

 substance containing amidine. 



Fibrous amidine (amidine tegumentaire ) is procured by 

 boiling one part of fecula with 200 parts of water, for a 



